Note: those who look for the bug "/background @mywindow myimage" plz look here. . this posting covers a different issue

if the background images are too large, the amount of windows where I can apply the background seems to have a certain limit. If this limit is exceeded, I get the error message "/background: unable to open <file>"
The error is strange: if this limit is exceeded and I open another mIRC instance (different mIRC directory!), I cannot apply the background at all. the error shows up already in the 1st window.
tested with winXP SP2, clean mIRC 6.21 and 6.3. no scripts, the command has been added manually: just /background -an image_file
Hardcopy of the mIRC-window with error message here.
background file here.
I confess: the background file (2000x2000 pixel) is much larger than my monitor size (1280x800). Reason: I wanted to ensure proper display on large monitors. I reckon in 2010 we can buy monitors twice the size of nowadays equipment. If you have a simple image file like mine it's easy to make a workaround. but if it is a large photo...

So I suggest to think about the method how mIRC fits the background image to the actual window size.

As you say this only happens with large files, I'm guessing that you are filling up the available memory that can be used for backgrounds. I don't know how memory is handled for backgrounds, so I don't know why you'd fill it up, but that sounds like the case.

hello Riamus,

1) it's interesting that the limit does not depend on the memory consumption of the image but on the image size in pixels. as to the max number of windows I can "background", there is no difference between an 8-bit gif and a 24-bit jpeg (same pixel size)
2) it confuses me that this limit, once it is reached, would apply in a new instance of mirc as soon as this 2nd instance is run in parallel to the 1st instance that caused the "background overflow". first I was thinking of some restrictions in winXP itself or in the graphic card. But in this case, bezillions of win users would run wild.

The reason why I'm interested in this issue: I always get a little bit nervous when I don't understand what's happening

Thanks, it appears that this was due to a memory limitation with one of the Windows API commands that I was using. The issue would only become apparent when loading very large bitmaps and/or opening many windows with a background picture. This issue has been fixed for the next version.